Question

at 7 p.m. last night, the temperature was 10 degree. at 7 a.m. the next morning the temperature was -2 degree. By how much did the temperature change from 7 p.m. to 7 a.m.? By how much did it changed each hour?

Answer 1

Change in temperature =  -2 - 10 = -12 degrees

rate of change per hour = -12 / 12 = -1 degree.

Answer 2

The temperature changed by 12 degrees in 12 hours meaning one degree per hour.